Long range hadron density fluctuations at soft pT in Au+Au collisions at RHIC

Dynamic fluctuations in the local density of non-identified hadron tracks reconstructed in the STAR TPC are studied using the discrete wavelet transform power spectrum technique which involves mixed event reference sample comparison. The two-dimensional event-by-event analysis is performed in pseudo-rapidity eta and azimuthal angle phi in bins of transverse momentum pT. HIJING simulations indicate that jets and mini-jets result in characteristic signals, visible already at soft pT, when the dynamic texture analysis is applied. In this analysis, the discrepancy between the experiment and the HIJING expectations for Au+Au at sqrt(S_NN)=200 GeV is most prominent in the central collisions where we observe the long range fluctuations to be enhanced at low pT, and suppressed above pT = 0.6 GeV.Comment: 10 pages, 5 figures, talk at the Xth International Wokshop on Multiparticle Production (Correlation and Flucutations in QCD), Istron Bay, Greece, June 8-15 200

Search for critical phenomena in Pb - Pb collisions

NA44 uses a 512 channel Si pad array covering $1.5 <\eta < 3.3$ to study charged hadron production in Pb+Pb collisions at the CERN SPS. We apply a multiresolution analysis, based on a Discrete Wavelet Transformation, to probe the texture of particle distributions event-by-event, by simultaneous localization of features in space and scale. Scanning a broad range of multiplicities, we look for a possible critical behaviour in the power spectra of local density fluctuations. The data are compared with detailed simulations of detector response, using heavy ion event generators, and with a reference sample created via event mixing.NA44 uses a 512 channel Si pad array covering $1.5 <\eta < 3.3$ to study charged hadron production in Pb+Pb collisions at the CERN SPS. We apply a multiresolution analysis, based on a Discrete Wavelet Transformation, to probe the texture of particle distributions event-by-event, by simultaneous localization of features in space and scale. Scanning a broad range of multiplicities, we look for a possible critical behaviour in the power spectra of local density fluctuations. The data are compared with detailed simulations of detector response, using heavy ion event generators, and with a reference sample created via event mixing